1. Field of the Invention
The invention relates to a prosthetic foot, more particularly to a prosthetic foot which includes a plastic foot body having a cavity that receives a spring and that is contractable upon deflection of the foot body to compress the spring.
2. Description of the Related Art
Referring to FIG. 1, a conventional prosthetic foot 1 is connected to a bottom portion of a limb rod of a prosthetic limb 2. The prosthetic foot 1 is designed to support the weight of the user in such a manner that body balance is maintained when the user is standing on a surface and that the foot 1 can react to the surface in a natural manner with the energy stored during pressing on the surface. However, since this kind of prosthetic foot 1 is made of metal/spring plate, which is highly flexible, the foot 1 cannot provide sufficient rigidity to support the weight of the user.
Therefore, the object of the present invention is to provide a prosthetic foot that provides good rigidity to resist severe deformation while maintaining sufficient resiliency to permit the prosthetic foot to act like a natural foot.
According to this invention, a prosthetic foot comprises a longitudinal foot body made of a plastic material, and a biasing unit. The foot body includes a front end portion, a rear end portion opposite to the front end portion, an upper surface that extends from the front end portion to the rear end portion, and a longitudinal cavity between the front and rear end portions and extending inwardly from the upper surface. The biasing unit is mounted in the longitudinal cavity, and has a first end extending toward the front end portion, and a second end extending toward the rear end portion. The foot body is deflectable to deform the upper surface and to cause the cavity to contract. The biasing unit is subjected to a compression force when the cavity contracts, and restores the upper surface to a normal position thereof when the compression force is relieved.